Re: Polynomial regression - Warning

[Adrian Custer <acuster gmail com>]

Lovely repartee, just the sophisticated answer that gnumeric brings to
the spreadsheet world.

Any chance you can craft this into a good popup dialog? e.g.

        You are trying to use SOME_METHOD which exists in gnumeric only
        to allow compatibility with other older spreadsheet programs.
        The computations involved in that method are known to be
        exceedingly problematic. However, you might be able to solve
        your problem using SOME_OTHER_METHOD. Would you like to use that
        instead?

Of course, this is all over my head. I'm merely hoping to leverage your
40 years of knowledge into a helpful dialog.

--adrian


On Tue, 2007-10-09 at 14:46 -0400, Prof J C Nash wrote:
> Polynomial regression was where I came into numerical analysis at the 
> beginning of my academic career 40 years ago. It is a dangerously 
> ill-conditioned problem, meaning that the regression parameters are 
> untrustworthy, though the "fit", i.e., the model, may be useful if the 
> calculations are done properly. There are ways of doing it that are 
> "less dangerous" using orthogonal polynomials.
>
> Just a warning that it should not be a high priority to add. Let the 
> Excel users drive off the cliff. If it is added for Excel compatibility, 
> then I'd still recommend a "Gnumeric does Vista" and pop up warnings 
> asking if the dangerous move should be allowed. Come to think of it, one 
> could borrow exactly the Vista popups so folk would blame Bill.
>
> Seriously, think if you really need polynomial regression or can use a 
> less troublesome approach.
>
> JN
>
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